Tuesday, March 04, 2008

In my latest study I am looking at the stolen base value from the 2007 from the Dodgers top base stealers. What I have done is gone through the 2007 play logs using the wonderful website Fangraphs.Com and looked at the win probability added (WPA) and the leverage index (LI) of each stolen base attempt. I am not including stolen bases of second base as part of the backend of a double steal. I am giving the credit in that case to the runner stealing third base. For each player, I've come up with the total WPA by adding the WPA from stolen bases and subtracting the WPA from unsuccessful attempts (and pickoffs). I've also calculated the average leverage index for each stolen base attempt, to determine which base runners are actually trying to steal meaningful bases the most. A stolen base in a one-one eighth inning tie will have a much higher leverage index than an attempt in a 4-0 2nd inning game. I have selected the Dodgers top four base stealers of 2007 to look at. They are Juan Pierre, Rafael Furcal, Russell Martin and Matt Kemp. Please keep in mind that the average Leverage Index is 1.0, anything higher than that is higher leverage and anything below that is lower leverage. Please see the table below.

2007 Dodgers, BaseRunning Study

Player

Average LI

Ave LI on SB

Ave LI on CS

Total WPA

Runs Added

Linear Weights Wins

Linear Weights Runs

WPA / SB Attempt

Juan Pierre

1.221

1.295

0.946

0.648

6.804

0.726

7.620

0.008

Rafael Furcal

1.086

1.061

1.190

0.277

2.909

0.307

3.220

0.009

Russell Martin

1.366

1.377

1.344

-.076

-.798

0.072

0.760

-.003

Matt Kemp

1.330

1.473

1.072

0.047

0.494

0.008

0.080

0.003

Ok, now what does all of this tell us. It says that Juan Pierre's base stealing exploits were worth nearly 6.8 runs or 0.648 wins last year. So while Juan Pierre is about 0.21 wins below "replacement level" as a left fielder his base running abilities are the only thing keeping him in the league.

Russell Martin and Matt Kemp are attempting steals in the highest leveraged situations on average (1.366 and 1.330 respectively). Juan Pierre is a fairly close third and Rafael Furcal a distant 4th. Furcal does a good job of picking and choosing when to steal, but can't always be counted on to steal in a high leverage situation. Russell Martin, while the bravest base stealer on the Dodgers, was not very efficient and probably would've been better off staying put a little more, especially in high leverage situations. Juan Pierre and Matt Kemp had the best success at stealing bases in higher leverage situations and getting caught only in lower leverage situations on average. Rafael Furcal made up a lot of ground by only getting caught 6 times, while swiping 22 bags. Let's take a quick look at the extremes in LI on successful and unsuccessful stolen base attempts.

Player

(High LI) SB

(High LI) CS

Juan Pierre

5.40

1.39

Rafael Furcal

3.04

1.87

Russell Martin

2.97

4.27

Matt Kemp

3.11

1.24

In conclusion the Dodgers have three good base stealers, Pierre, Furcal and Kemp. Russell Martin would be advised not to steal in such high leverage situations. He has a propensity for being caught in high leverage attempts. I see nothing wrong with allowing the other three to steal when appropriate.